'The Summoning' is the second book in the Trilogy 'Throwback', which consists of 'Legacy', 'The Summoning' and 'Time Meld' (Working Title).
Although 'The Summoning' can be read as a 'stand alone' book, the back story makes much more sense if 'Legacy' is read first.
'Legacy' is available in Kindle ($2,99), or in 6" x 9" softcover formats.
To read sample chapters of other books in the series 'The Chronicles of the White Tower',
The Summoning (Vol - 1) Chapters 11 - 15
The Summoning (Vol - 1) Chapters 6 - 10